How do I reset my Network settings to default (Ubuntu 16)?

I messed up my network settings through the command line. I have a headless Ubuntu Server 16.04 without any desktop environment installed for a lighter-weight installation and connected to my local network through ethernet, and I use a Windows 10 laptop with SSH to access it, so I do not have a extra screen to use to reinstall Ubuntu. Is there any way to reset all my network settings through the command line?

What exactly happened was: I was playing around with the command line because I wanted to access my server through SSH without typing in an IP address every time I connected, so I used sudo hostname with all its possible arguments to change its hostname from an IP address to my name. Now, SSH, SFTP, FTP, SMB, HTTP and almost everything possible is a million times slower than usual and sometimes returns "Took too long to load".

I don't mind resetting the entire OS, but I don't have an screen/monitor to use with a bootable USB/DVD. I need a solution because my website is getting affected - It takes about 45 seconds to load a 8.2MB webpage although my internet speed is above 10MBPS.

SSH is working relatively better, so is there any command-line solution to my problem?

Run

ifconfig

and see the name of your network adapter. Mine is: enp0s3

now run this command

sudo nano /etc/network/interfaces

and you should get something inside....delete everything and paste this (but change the network adapter name where enp0s3 is):

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto enp0s3
iface enp0s3 inet dhcp

save the document and reboot...